Background of the invention

The invention relates to a milk/air separator, to a milking device comprising a milk/air separator of this type, and to a milking assembly comprising a number of milking devices of this type.

Milk/air separators are traditionally used to remove the air, which enters the milk during milking, out of the milk again. Air separators of this type are usually accommodated in a collecting conduit in which the milk is commonly discharged from a plurality of milking claws to a storage vessel. In addition, the traditional device for milking often comprises a measuring device in order to measure the milk delivery of each animal. That is often still the solution even in a modern milking assembly using a robotized system which is computer-controlled and wherein even the feed delivery and the further milking assembly are controlled or else regulated by means of the computer. Automated systems of this type are supplied inter alia by van der LeIy, by Insentec and by DeLaval, to name but a few of the more well-known suppliers. In addition, automated systems of this type still continue to operate using a traditional milking principle according to which the milking claws are connected to a central reduced pressure system. In this case, each animal is connected to the same reduced pressure or underpressure.

WO 93/22902 discloses a milk/air separator provided with an extensive receiving space into which the milk flows. From the receiving space, the milk flows into an inlet chamber from which the milk subsequently flows into a substantially horizontal cylinder. This milk/air separator is difficult to clean. In addition, the measuring of milk volumes is not optimal. Nor is it possible to completely empty the cylinder in this design.

From the applicant, a milking assembly is known from inter alia WO 2008/097093 in which the reduced pressure is generated by means of an ejector which generates reduced pressure by means of overpressure or compressed air. This allows the reduced pressure to be generated locally, even for each animal. However, it was found that the described milking assembly is capable of further improvement. It has been found that this improvement may also be applied in traditional milking assemblies.

Summary of the invention

The object of the invention is to provide an improved milk/air separator.

A further or else supplementary object of the invention is to provide a milk/air separator allowing the milk delivery to be measured.

An additional or else supplementary object of the invention is to provide a milk/air separator which can be used for an individual dairy animal.

The invention provides for this purpose a milk/air separator comprising a cylinder which in operation is substantially vertical and is provided with an outlet for milk at an end of the cylinder, an inlet for milk at a distance from the outlet, a piston body which is up and downward moveable inside the cilinder and is drivably coupled to a drive device for moving the piston body up and downward inside the cilinder from a bottom position to a top position, wherein the piston body comprises at least one liquid passage which is provided with a block for said liquid passage in order to press milk out of the cylinder during displacement of the piston body from the top position to the bottom position, and wherein the milk/air separator is further provided with a passage at an upper end of the cylinder above the top position and which is connectable to a reduced pressure device for generating a reduced pressure inside the cilinder, and a level sensor for measuring a level of liquid between the bottom position and the top position.

As a result of the cylinder with the piston body, it is possible to provide a milk/air separator which allows the amount of milk delivered to be measured. Furthermore, the milk/air separator can be used on an individual dairy animal on account of the simplicity with which said milk/air separator can be implemented, and the scalability. Thus, for example, selecting a transparent cylinder material can also provide a visual inspection means which a herdsman can use to monitor or inspect the milk delivery and/or quality of individual animals. Furthermore, reduced pressure is generated inside the cilinder itself, as a result of which more effective deaeration of the milk occurs.

The invention further relates to a milking device comprising the milk/air separator according to the invention, and a control device which is operatively coupled to the milk/air separator. In particular, the control device is configured for providing control signals to the drive device. In one embodiment, the control device is operatively coupled to the level sensor of the milk/air separator if present. In a further embodiment, the control device is configured for issuing one or more control signals to the drive device on the basis of a signal from the level sensor.

It has been found mat the milk/air separator can in this way be used effectively in an automated milking system. In one embodiment, the rate of milk delivery can be defined by the control unit by means of the milk/air separator. The control unit can control the level of reduced pressure in the milk/air separator on the basis of the milking rate. The control unit can also regulate the level of overpressure and/or the variation thereof in the teat cups on the basis of the milking rate. That can be implemented in a simple manner by means of the milk/air separator.

The invention further relates to a milking assembly comprising a number of milking devices as described above, comprising a milking computer for regulating the milking of a herd, which milking computer is operatively coupled to each of the milking devices, and wherein in particular the milking devices are connected to a common milk depot.

It has been found that the milking device can easily be embodied as what is known as a plug-and-play unit. This allows the milking capacity to be easily adapted, if desired, to a desired capacity by an additional milking device. In addition, in the event of malfunction, a defective milking device can be replaced very easily while the defective device is repaired. If desired, a herdsman can stock a reserve for that purpose. In one embodiment, the level sensor is configured to measure the continuous level of liquid between the bottom position and the top position. This allows the height of the liquid inside the cilinder to be precisely defined. This allows precise measurement, especially if a capacitive liquid sensor is used, and the cylinder can achieve the precision of a graduated cylinder. Other level sensors known to the person skilled in the art can also be used for this purpose. The level sensor is operatively coupled to a regulating device which regulates, for example speeds up or slows down, the drive on the basis of measured values. It is even possible to thereby control the reduced pressure on the milking claw. After all, the flow rate of the milk from the milking claw may be defined from the pumpage of the cylinder. In combination with a plastics material or glass cylinder, the capacitive level sensor is very effectively applicable and precise.

In one embodiment, the piston body comprises at least two piston body parts which, when at a distance from one another, have between them a liquid passage and, pressed together, close off the liquid passage in a liquid-tight manner.

This allows a good separation to be obtained by exerting pressure on the milk by means of the piston body.

In one embodiment, a Fust of the piston body parts is coupled to the drive device in order to press the piston body parts together in a liquid-tight manner during displacement of the piston body from the top position to the bottom position.

In operation, milk can flow in during displacement of the piston body from the bottom position to the top position. Said milk can flow through the liquid passage to the space below the piston body and fill said space. Air and foam are then left above the piston body.

In one embodiment, the milk/air separator further comprises a second piston body part which rests against the cylinder wall in a substantially liquid-tight manner; in one embodiment, even in an almost air or gas-tight manner, as a result of which air can also be pumped in order to empty the cylinder. In one embodiment, the second piston body part is substantially annular with a central opening.

This allows two mutually sealing piston body parts to easily be made.

In one embodiment, the first piston body part has a larger cross section than the central opening, in particular the first piston body part forms, when placed on the second piston body part, jointly therewith a substantially liquid-tight piston body. This allows a seal to be improved.

In one embodiment, one piston body part comprises holding parts in order to remotely arrest another piston body part in such a way that the piston body parts are displaceable with respect to each other between a position one on the other to a position at a distance from each other, in particular displaceable in the direction from the bottom position of the piston body to the top position of the piston body or vice versa.

This allows milk easily to enter the space below the piston body during the ascending movement of the piston body, and the milk can be pushed away or pressed with little air during the descending movement of the piston body. In one embodiment, the piston body closes a space between the piston body and the outlet in order to be able to pump air. In the last strokes after almost all the milk has been pumped away, the last remnant of milk can then be pushed out of the cylinder and the conduit by pumping a small amount of air. This also has an advantage during cleaning after use.

In one embodiment, the piston body parts, when at a distance from one another, have a liquid passage between them. Liquid and air are separated in a simple manner. Liquid can flow through the liquid passage to below the piston body, for example during the ascending movement. In one embodiment, the inflow is then greater than the flow through the liquid passage so that the piston body is actually in the liquid and air and any foam form above the piston body.

In one embodiment, the holding parts are located on the side of the piston body opposing the bottom position, and a piston body part can move with respect to another piston body part in the direction of the top position of the piston body.

In an embodiment wherein the cylinder comprises a closure part near the bottom position of the piston body, the inner shape of the closure part and the part of the piston body that faces that closure part are substantially adapted to each other.

As a result, as little milk as possible is left behind after each stroke and the pumped volume can be measured more precisely. In addition, the milking rate may be deduced therefrom.

In one embodiment, the outlet is provided in the bottom part of the closure part. The pumped volume is readily measurable.

In one embodiment, the milk/air separator further comprises a level sensor for ascertaining the presence of a liquid, in particular of milk, inside the cilinder, in particular inside the cilinder wall.

This allows the milk/air separator to be automated.

In one embodiment, the level sensor is arranged between the inlet and the top position of the piston body.

In operation, the piston body is preferably held in the milk so that foam and air collect above the piston body, thus preventing concomitant pumping of air as much as possible.

In one embodiment, the inlet is provided above the top position of the piston body.

In one embodiment, the milk/air separator further comprises a flow distributor between the inlet and the top position, in particular the flow distributor comprises a flow body which, viewed from the inlet, is convex. For example, a spherical part is suitable. Excessive foam formation inside the cilinder is prevented as much as possible. Alternatively, the inlet can open out into the cylinder substantially tangentially to the cylinder wall in order to prevent the formation of foam as milk flows in. It is in this case conceivable to arrange the inlet substantially tangentially and directed downward at an angle. Milk will then flow in along the cylinder wall and thus prevent foam formation still further.

In one embodiment of the milk/air separator, when provided with the level sensor, the level sensor is provided between the flow distributor and the top position. This disturbs the operation of the level sensor as little as possible.

In one embodiment, the drive device comprises an electric motor with an eccentric, in particular the eccentric is coupled to the piston body in order to generate a stroke of the piston body between the bottom and top positions for each revolution. A simple electric motor thus allows the production, at little cost and without complex provisions, of a milk/air separator allowing, in addition, the milk yield, and for example also the milking rate, to be measured. Alternatively, an air-driven cylinder, hydraulic cylinder or other drive could be used. The stroke volume and the stroke frequency can be used to measure the outlined variables.

In one embodiment, the milk/air separator further comprises a prestressing part for prestressing the piston body with a force in the direction of the bottom position, in one embodiment an almost constant force during the displacement of the piston body from the top position to the bottom position, in one embodiment the prestressing part comprises at least one spiral spring, in one embodiment arranged substantially parallel to the axis of the cylinder. As a result, a drive device with limited power is sufficient. A compression spring or gas spring could also be used instead of the springs.

In one embodiment, the prestressing part comprises a curved tube with two ends substantially parallel along the cylinder with the tips at the upper end of the cylinder, in one embodiment one or more spiral springs for prestressing extend in the tube ends. This allows spiral springs to be used easily and inexpensively. Fitting the springs in the extended state provides an almost constant force over the stroke of the piston body.

In one embodiment of the milking device comprising the milk/air separator according to the invention, said milking device comprises a control device which is operatively coupled to the milk/air separator; in particular to the drive device for providing control signals to the drive device. More particularly, the control device is operatively coupled to the level sensor of the milk/air separator if present. More particularly, the control device is configured for issuing one or more control signals to the drive device on the basis of a signal from the level sensor; the milking device according to the invention further comprises a reduced pressure device for generating reduced pressure. In this case, the reduced pressure device can be operatively coupled to the milk/air separator for reducing the pressure inside the cilinder in operation. This allows the control device to be integrated into the milking process as outlined.

hi one embodiment of the milking device, the control device is operatively coupled to the reduced pressure device for regulating the reduced pressure. In particular, the milk/air separator is provided with a pressure sensor, hi particular, the pressure sensor is provided inside the cilinder or else in a reduced pressure connection thereof. The pressure sensor can be operatively coupled to the control device for controlling the reduced pressure device on the basis of one or more signals from the pressure sensor. This allows a milking device to be provided that is to a high degree autonomous.

hi one embodiment of the milking device, the reduced pressure device comprises at least one ejector or else at least one venturi which is connectable to a compressed air or overpressure conduit, for providing a reduced pressure on the milking device, hi one embodiment, the reduced pressure device further comprises an adjustable valve in the compressed air of overpressure conduit, hi this case, in one embodiment, the adjustable or else a proportional valve is operatively coupled to the control device for controlling the reduced pressure, hi one embodiment, the adjustable valve or proportional valve is controllable on the basis of a signal from a pressure sensor, such as a pressure sensor in the milk/air separator. The embodiment of the milk/air separator makes it particularly suitable for a control of this type.

In one embodiment, the milking device further comprises a milking claw provided with a milk conduit which is fluidically connected to the inlet of the milk/air separator, and a conduit which is operatively coupled to the reduced pressure device, hi particular, an individual milking claw is fluidically connected to the milk/air separator. As a result, in a milking system, each milking claw has a milk/air separator. This improves operation and, in addition, a separate flow meter or other meter is not necessary for measuring the flow rate of the milk flow.

In one embodiment, the milking device further comprises a housing provided with the milk/air separator, the reduced pressure device and the control device. In addition, if the milking claw is used in accordance with the aforementioned prior patent applications of the applicant's, individual pressure regulation for each milking claw and even for each teat cup is possible. In one embodiment, the housing further comprises a pressure pulsator which is connected to the reduced pressure device and which is connectable to a milking claw. This pressure pulsator can be of a generally known sort with which a person skilled in the art is familiar. In one embodiment, the cylinder of the milk/air separator extends at least partly outside the housing. This allows the herdsman to visually monitor the milking process and milk quality for each animal.

In one embodiment of the milking device, the control device is operatively connectable to a milking computer for regulating the milking of a herd. The milking device is well suited for this purpose as a result of its high degree of autonomy, and may easily be employed in said way.

In one embodiment of the milking device, the control device is a regulating device for regulating the operation of each of the devices connected thereto. In particular, the regulating device regulates on the basis of signals from one or more sensors issuing a signal concerning the operation of the associated device. The autonomy of the device increases as a result of the feedback of the operation by means of the sensors.

In one embodiment, in the milking assembly comprising a number of milking devices with a milking computer for regulating the milking of a herd, the milking computer is operatively coupled to each of the milking devices. In one embodiment, the milking devices are connected to a common milk depot. In fact, the milking devices require a connection for the supply of electrical power, a data connection and a compressed air or reduced pressure connection and a milk discharge link in order to be able to operate. A milking capacity of a milking assembly is in this way easy to adapt by adding or removing a milking device.

In one embodiment of the milking assembly, the milking computer is also operatively coupled to a feed dispensing device for dispensing feed to the herd, in particular to individual animals, in particular during milking by means of a milking device.

In one embodiment of the milking assembly, the link for exchanging data from the milking devices with the computer is wireless, such as by means of WiFi, Bluetooth, ZigBee or similar electromagnetic operative links.

This increases still further the autonomy and the simplicity of a shed arrangement. This means that there are also fewer parts that can malfunction.

The invention further relates to a milking device comprising a housing provided with a milk/air separator and a connection for a milking claw which in the housing is fluidically connected to the milk/air separator by means of a flexible liquid conduit and in the housing is connected to a reduced pressure device in the housing by means of a flexible air conduit, wherein the housing is further provided with a hoisting device for hoisting the milking claw to the housing.

This further reduces the risk of damage and allows a further compact shed arrangement.

It will for that matter be clear that the invention relates to the milking of dairy animals. Primarily, this will concern cows, but the invention can also offer a solution for other dairy animals such as goats, sheep or the like.

Furthermore, it will be clear that the various aspects of the invention offer advantages, in particular, in combination with the reduced pressure device on a vacuum or reduced pressure device that is driven by a fluid under overpressure. This reduced pressure device is expressly described in certain prior patent applications of the applicant's, such as PCT/NL2008/050074 and PCT/NL2008/050148. These documents must therefore be regarded as being fully incorporated into this application. For some jurisdictions, the combined subject matter may be regarded as a continuation, such as for example a continuation-jn-part. Specific elements of the reduced pressure device can be combined with the various aspects of the present invention. As a result of the possibility of obtaining reduced pressure at a desired location or moment, and in an adjustable manner, it has proven possible to implement a compact milk/air separator and in particular a compact milking device which is a controllable, in particular adjustable. The milking device may readily be accommodated in a milking assembly as a unit which is to a high degree autonomous.

For that matter, the invention further relates to a liquid/gas separator comprising a cylinder provided with an outlet for liquid at an end of the cylinder, an inlet for liquid containing gas at a distance from the outlet, a passage at an upper end of the cylinder that is connectable to a reduced pressure device for generating a reduced pressure inside the cilinder, and a piston body which is up and downward moveable inside the cilinder and is drivably coupled to a drive device for moving the piston body up and down inside the cilinder from a bottom position to a top position, wherein the piston body comprises at least one liquid passage provided with a block the liquid passage to press the liquid with an at least reduced amount of gas out of the cylinder during displacement of the piston body from the top position to the bottom position. The embodiments and further developments and characteristics outlined for the milk/air separator can also be applied to this liquid/gas separator. A number of the advantages outlined in this application may also be obtained therefor. However, when used in a milk/air separator, the device has the outlined advantages to a particularly high degree.

The invention further relates to a milk/air separator comprising a cylinder provided with an outlet for milk at an end of the cylinder, an inlet for milk at a distance from the outlet, a passage at an upper end of the cylinder that is connectable to a reduced pressure device for generating a reduced pressure inside the cilinder, and a piston body which is up and downward moveable inside the cilinder and is drivably coupled to a drive device for moving the piston body up and down inside the cilinder from a bottom position to a top position, wherein the piston body comprises at least one liquid passage provided with a block which is operably connected to the drive device. This allows simple operation and control which is furthermore safe to operate.

The invention further relates to a milk/air separator comprising a cylinder provided with an outlet for milk at an end of the cylinder, an inlet for milk at a distance from the outlet, a passage at an upper end of the cylinder that is connectable to a reduced pressure device for generating a reduced pressure inside the cilinder, and a piston body which is up and downward moveable inside the cilinder and is drivably coupled to a drive device for moving the piston body up and down inside the cilinder from a bottom position to a top position, wherein the piston body comprises at least one liquid passage which is provided with a block for the liquid passage in order to press milk out of the cylinder during displacement of the piston body from the top position to the bottom position.

This milk/air separator can also be provided with each of the characteristics and features mentioned in this description and the sub-claims.

The invention further relates to a device provided with one or more of the characterizing features described in the appended description and/or shown in the appended drawings, or else to a method provided with one or more of the characterizing features described in the appended description and/or shown in the appended drawings.

It will be clear that the various aspects mentioned in this patent application can be combined and/or each considered separately for a divisional patent application.

Brief description of the figures

The appended figures illustrate an embodiment of a milking device and a milk/air separator for a milking device according to the invention, hi the figures:

Figure 1 is a perspective view of an embodiment of a milking device according to the invention; Figure 2 is an open view of the milking device from Figure 1, showing the interior;

Figure 3 shows a milk/air separator according to the invention;

Figure 4 is a side view of Figure 3;

Figure 5 is the cross section AA from Figure 4; and

Figure 6 is a schematic control diagram of an embodiment.

Description of embodiments

Figure 1 shows an embodiment of a milking device 1. This milking device 1 is provided with a milking claw 2 with teat cups 3. This may be a normal milking claw 2 with normal teat cups 3, for example operating by means of a reduced pressure or vacuum facility which supplies air under reduced pressure. Alternatively, use may be made of a milking claw as described in the applicant's WO 2008/097093. The milking claw is connected to the housing 5 and the components accommodated therein by means of the milk conduit 4 and (reduced) pressure conduits.

The milking device 1 comprises a housing 5 which in this case is provided with a reproduction device 6 on which important information can be reproduced for a herdsman. This reproduction device 6 can for example be an LCD display or a similar device. Furthermore, the housing 5 is in this case provided with an input device 7 which a herdsman can use to input operational information, for example.

A milk/air separator 8, which also forms part of the invention, may be seen protruding below the housing 5. This milk/air separator 8 comprises a transparent cylinder in which the milk obtained is collected. The milk/air separator 8 will be described in greater detail hereinafter. For protection, the milk/air separator 8 is also provided with a protective rod 9, usually a hollow, curved tube. In this case, this also forms part of the milk/air separator 8. The milk/air separator 8 separates the milk and the air and will usually pump the milk, from which most of the air has been removed, further to a storage vessel (not shown).

In this case, the housing 5 is also provided with a hinging door 10. In this embodiment, control electronics (not shown), the reproduction device 6 and the input device 5 are fastened to this hinging door 10. As a result, all the components of the milking device 1 are well separated and readily accessible. Furthermore, this allows components or parts thereof to be easily replaced in the event of malfunction.

The housing and the components in the housing produce a milking device which is simple to install. In addition, the final dimensions and capacity of a shed milking arrangement, which usually comprises a plurality of milking devices, are easy to adapt by adding or removing a milking device. The housing can be made fully operative by connecting the milking device to a power supply for electrical voltage, a milk discharge conduit to discharge milk to a collecting storage vessel, an air conduit for air under reduced pressure or else overpressure, and a data connection to send data from a central controller to the milking device 1 and to send data from the milking device to the central controller.

Figure 2 shows the various components in the milking device 1, the door 10 being omitted. In this case, a reduced pressure device 12 for providing a reduced pressure is provided in the housing 5. The reduced pressure device 12 is also provided with two reduced pressure vessels 13, 13'. Two reduced pressure vessels 13, 13' which are air- connected by means of an air conduit 14 have in this case been selected in order to make the housing 5 as compact and functional as possible. The reduced pressure vessels 13, 13' are air-connected by means of the reduced pressure conduit 15 to the milk/air separator 8 and by means of the reduced pressure conduit 15' to a pulsator 17 for issuing pulsed reduced pressure to the teat cups 3 by means of pulse conduits 18. In milking technology, the pulsator 17 is known per se to the person skilled in the art and can be connected to teat cups which are universally known per se.

In this case, a milking claw hauling device 19 is also provided in the housing 5. This milking claw hauling device 19 has in this case a cylinder with a cylinder rod which is connected to a first roll and a fastening eye for a cable (not shown) which at a different tip is connected to the milking claw 2. Furthermore, the milking device 1 is provided with a second roll which is fixed with respect to the first roll. The cable then runs from the eye over the first roll 20', the second roll 20, and subsequently to the milking claw 2. The displacement of the first roll 20' will cause the cable to be shortened three times with respect to the milking claw 2, as a result of which the milking claw 2 is brought to the housing 5. A first roll 20' which is displaceable in the housing 5 and has, arranged fixedly thereon, a cable connecting part and a second roll 20 arranged fixedly in the housing are in this case used.

Figure 3 is a perspective view of the milk/air separator 8. The milk/air separator, for which independent protection is also sought in this patent application, comprises a cylinder 21 provided with a piston body 22 which can move up and down therein. The piston body 23 is drivably coupled to a drive 24 by means of a rod 23. At the tips, the cylinder 21 is connected by means of a bottom closure plate 28 and a top closure plate 27. Both closure plates are clamped to each other by means of the protective rod 9. In particular, the bottom closure plate 28 is in this case securely connected to the protective rod 9. The tips of the protective rod 9 reach with a threaded tip through the top closure plate 27 and clamp by means of nuts 29 screwed onto the threaded tip the tube forming the cylinder 21 between the closure plates 27 and 28. Of course, various other possibilities of clamping will be clear to the person skilled in the art. The solution selected in this case has the advantage that the protective rod has a clamping action and a protective action. In addition, an aesthetically pleasing design is also produced that is also, moreover, simple and relatively inexpensive to make. Now, selecting the tube of the cylinder 21 so as to be made of glass improves the aesthetic aspect still further. In addition, a viewing window, through which the herdsmen can visually monitor the milk quality and the process, has been produced as a technical advantage, especially as the design is selected in such a way that the cylinder protrudes partly from the housing. An aesthetically attractive design is also presented.

Because a curved hollow tube has been selected, the protective rod 9 has still a further function of use in this case. Springs, which are connected to a transmission part 25 coupled to the drive rod 23, are fastened in the hollow tube ends. When the piston body 22 is at the bottom of the cylinder 21, the springs 26 will be stress-relieved, in one embodiment remain somewhat stressed (stretched). When the piston body 22 is hoisted, the springs will be further stressed. If milk, which has to be pumped, has now collected below the piston body 22, the springs 26 will assist the drive so that a lighter drive 24, which will for that matter be commented on hereinafter in greater detail, is sufficient. As a result, the piston body 22 is provided with a prestressing device in order to prestress the piston body 22 in an upper position for providing a force forcing toward the lower position.

The milk conduit or milk hose 4 reaches into the cylinder 21 of the milk/air separator 8 and has, in this case roughly halfway up, a mouth 30. The mouth is in this case tapered in order to allow a smooth outflow with as little foam formation as possible. In addition, a flow distributor 31 is provided in the jet direction. The selection of a curved part, which is convex in the jet direction, of a sphere prevents foam formation still further.

A measuring sensor 32 is provided just below this flow distributor 31 in order to detect the presence of milk. The sensor is configured to indicate when the level of milk has reached the height of the level sensor 32. The position of the level sensor 32 is selected so as to minimize malfunctions, In many cases, a second, safety sensor, often of the same type as the level sensor 32, will be provided at the top of the cylinder 21. If the level sensor 32 fails, this safety sensor can issue a signal if the milk threatens to rise too high. Alternatively, or in addition to the aforementioned sensors, the cylinder 21 can be provided with sensors for measuring the level of liquid inside the cilinder 21. Figure 4 shows a sensor 51 of this type. In one embodiment, a capacitive liquid level sensor 51 has in this case been selected. An example of a suitable sensor is the CLC-series miniature capacitive continuous liquid level sensor from Sensortechnics. A capacitive sensor of this type can measure a level of liquid through a glass or plastics material partition. This allows the movement of the piston body 22 to be controlled with even greater precision, and thus the amount of pumped milk also to be controlled very precisely. A high precision of better than 1 % has been found to be possible. In addition, it is also possible to monitor the milk delivery rate of an animal. The device has thus also obtained a flow meter function. In one embodiment, two level measuring sensors 51 of this type can be used. The level measuring sensors allow the cylinder 21 to be used as a digital graduated cylinder because the continuous level of liquid can be measured. That is to say, the height of the liquid inside the cilinder can be defined. This sensor is even able to measure the border between liquid and foam.

Figure 4 is a side view of the milk/air separator 8 from the foregoing figures. This view additionally shows the reduced pressure connection 33 which connects the reduced pressure device to the milk/air separator 8 via the reduced pressure vessels 13, 13' for providing a reduced pressure inside the cilinder 21.

Figure 4 also shows a non-return valve 34 which can close off the milk discharge conduit 11 to prevent milk from flowing back into the milk/air separator 8. This will prevent backflow above all at the end of a milking round, when the last milk has to be pumped. The parts within the cylinder 21 are omitted from this view for the sake of clarity.

Figure 5 is the cross section from Figure 4 as indicated. This figure clearly shows how the springs 26, as the prestressing means, extend in the tube ends of the protective rod 9. It will be clear that other means for prestressing are also possible, such as a pressure cylinder or a rubber material, for example. However, the selected solution is inexpensive, simple to make and to adjust, and allows a taut and strong design with aesthetic charisma. As a result, the embodiment provides a counterpressure device which exerts, when the piston 22 is in its top position, a force acting in the pumping direction. The action ensures that the drive has to exert, as much as possible, a constant force during the piston movement. In one embodiment, the counterpressure device will still exert a force acting in the pumping direction even in the bottom position of the piston 22. In one embodiment, the force exerted by the counterpressure device will be roughly half the force that the piston 22 has to exert during the pump stroke or else the travel downward.

Furthermore, the selected embodiment of the drive 24 has also been made clearly visible in the figure. In this case, an electric motor (to which reference numeral 24 refers) is provided with an eccentric 35. An arm has been selected having at one tip a wheel or bearing 36 which contacts die transmission part 25. This embodiment of the drive 24 is inexpensive, simple and has low susceptibility to malfunction. In addition, the pressure has been found to obtain in this way precisely the correct build-up and reduction, thus preventing shocks in the milk discharge conduit 11. The cylinder with the piston body allows the amount of milk to be measured at the same time. This allows a further function to be imparted to the milk/air separator. In the selected solution, it is even possible to count just the strokes of the electric motor in order to measure the total amount of milk delivered. As described hereinbefore, the prestressing of the piston, in its top position down toward its bottom position, allows a relatively light electric motor. Alternatively, instead of an electric motor, it is possible to select a motor driven by means of compressed air, for example. A direct drive of the piston body is also possible. It is for example conceivable in this regard to form a pressure chamber at the position where the wheel 36 is now placed.

Figure 5 also clearly shows the construction of the piston body 22. The piston body 22 comprises in this case a first piston body part 37 which is in this case provided with a ring seal 38 for a good seal from the cylinder inner wall. The piston body 22 further comprises a second piston body part 37. This second piston body part 37 is coupled to the drive 24, in this case securely connected to the drive rod 23. The second piston body part 37 can in this case move up and down with respect to the first piston body part 37. Furthermore, the piston body 37 is provided with holding parts 40 in order to arrest the second piston body part 37 remotely from the first piston body part 38. This produces, during an ascending displacement of the piston body 22, an opening through which liquid can flow. Furthermore, the first and second piston body parts are mutually shaped in such a way as to rest, when pressed together, against each other in an almost entirely liquid-tight manner. The embodiment illustrated in this figure is simple and operationally safe to implement. This allows collected milk to be pumped effectively while, in addition, the milk and air are clearly separated. It is conceivable to achieve the same functionality in a different manner, although care must be taken to prevent foam from forming in milk which is readily foamable per se. The piston body 22 then comprises at least one passage which provides, during an ascending displacement of that piston body 22, a fluidic connection between the cylinder space above the piston body 22 and the cylinder space below the piston body 22. The passage is provided with a closure means which closes off in a liquid-tight manner the at least one passage of the piston body 22 during the descending movement of the piston body 22. In other words, the piston body 22 comprises a non-return valve.

Figure 6 shows schematically a milking device with a regulating device 50. In this outlined embodiment, this regulating device 50 is provided in the housing 5. This produces a compact device as has also been discussed hereinbefore, hi the outlined embodiment, a reduced pressure device 12, a milk/air separator 8 and a drive for a milking claw 22, in this case of the traditional type, by means of a pulsator 17, are also provided in the housing 5. The pulsator 17 has a pressure conduit 18 running to a milking claw 22 outside the housing 5. From the milking claw 22, a milk conduit 4 runs to the milk/air separator 8 in the housing. More precisely, a part protrudes outside the physical walls of the housing 5, while forming part thereof. Furthermore, a number of sensors are provided in the housing that issue a status to the regulating device 50. The milk/air separator 8 has a level sensor 32 or 51 (described hereinbefore) and is driven by means of a drive device 24. The drive device receives a control signal from the regulating device 50, but can also issue a status signal, or else a signal which can be used to identify a position, for example a bottom point of the piston body 22 (described hereinbefore). Furthermore, a pressure sensor 49 is in this case provided in the milk separator 8. The pressure sensor 49 indicates the pressure to the regulating device 50. The regulating device 50 compares this value to a set value and controls, in this case by means of a proportional valve 48. The flow of compressed air L is thus controlled in this case. The reduced pressure device 12 can be provided with a venturi. This device contains two injectors which can be used to generate a reduced pressure in one or more pressure vessels (described hereinbefore). The reduced pressure device 12 may correspond to the vacuum generator as described in the applicant's NL 2000483. This provides further advantages on top of the advantages mentioned hereinbefore in this description. Thus, the milking device can be built compactly in one housing, is easily extendable and relatively energy-saving. The ejectors are then connected to a compressed air conduit. As a result, reduced pressure is generated locally at moments when it is necessary. In particular, a reduced pressure device can in this case be used to effectively regulate the pressure for an animal to be milked. As a result, the milking device according to the invention has a reduced pressure device for a single animal to be milked. In addition, reduced pressure is generated at the moments when it is necessary. In this case, the device 1 also receives electricity E and has data lines D. Via these data lines, the regulating device 50 can send data to a main computer managing a plurality of devices, and receive instructions therefrom.

In use, the milk/air separator 8 operates as follows. The reduced pressure device 12 reduces the pressure in the reduced pressure vessels 13, 13". The teat cups 3 are attached to the udders of a cow, for example, and milking commences. Milk begins to flow in via the milk conduit or milk hose 4. Via the mouth 30, the milk flows on the flow distributor 31 and runs into the cylinder 21 in as steady a manner as possible. In the meantime, the pressure inside the cilinder 21 has been reduced and is kept at this reduced pressure by means of the reduced pressure device 12. The piston body is in its bottom position in which, in one embodiment, the underside of the piston body 22 rests almost against the inner surface of the closure plate 28. A layer of milk begins to form above the piston body 22. The piston body 22 is displaced upward. This increases the volume of the space below the piston body 22. This increase in volume per unit of time is preferably less than or else at most equal to the volume of the inflowing milk. After all, the risk of an air space then forming below the piston body 22 is then as low as possible. In addition, in one embodiment, the throughflow resistance through the piston body 22 is less than the inflow resistance of the milk into the cylinder. As a result, during the ascending displacement, the piston body 22 is in the milk layer which is formed. During the ascending movement of the piston body 22, the milk flows through the passage in the piston body 22 and fills the increased volume below the piston body 22. The press stroke of the piston body 22 can commence when the level of milk in the cylinder 21 reaches the level sensor 32. In one embodiment, the level sensor 32 is above the top point of the piston body 22. The simplest provision therein is that the drive 24 is stopped provided that the level of milk has not yet reached the level sensor 32 and the piston body is in its top position. The drive 24 is activated when the level of milk reaches the level sensor 32. This produces a simple control, while little to no air is concomitantly pumped. The running speed of the drive 24 is in this case set to the maximum milk supply, but may possibly be settable for an individual animal to be milked if this becomes necessary.

In the outlined embodiment, from the top point of the piston body 22, the arm 35 will be positioned vertically with the wheel 36 above the shaft of the electric motor 24. As the electric motor continues to run, the piston body 22 moves downward. During the descending movement of the piston body 22, the milk is pressed out of the cylinder 21, and usually to a storage tank, via the milk discharge line 11. In the outlined embodiment from Figures 3-5, during the downward movement, the drive rod 23 pushes the second piston body part onto the first piston body part, as a result of which the piston body 22 becomes liquid-tight and can press away the pressurized liquid. As a result of the mutual shaping, there are hardly any to no air cavities below the piston body 22.

In one embodiment, once it has reached the bottom position, the piston body 22 will almost rest against the bottom closure plate 28. The arm 35 is then in a vertical position with the wheel 36 below the drive shaft of the electric motor.

The total volume of milk can be calculated from the fixed stroke volume produced in this embodiment.

If the supply of milk stops or else decreases to below a defined, often preset, level, the following situation will occur. An end programme then becomes operative. The piston body 22 will be in its top position for a certain waiting time without a signal being provided by the level sensor 32. An end programme then becomes operative. In this case, the last remnant of milk in the cylinder 21 and also a remnant of milk in the milk discharge conduit 11 is pumped past the non-return valve 34 by means of the air below the piston body 22.

As result of the fact that less reduced pressure is required inside the cilinder, the reduced pressure device will also operate at a lower speed or else be switched off.

The advantages that can be obtained by all or else some of the characteristics or else embodiments of the invention described in the present document are listed again below.

1. Animal-friendly; vacuum and pulsation controlled for the individual milk flow: • Lower teat tip loading • Better milk discharge as a result of higher vacuum in full milk flow

• Better stimulation of the cow as a result of more active milking during high milk flow

• Amount of milk increased somewhat (better opening of teat liner) • Shorter milking time

2. Hygienic

• No mutual influencing of cows

• Germ count lower, as a result of more compact installation

• Cell count better, as a result of cow-friendlier milking • Fewer veterinary medicines, less residue in the milk

• More easily cleanable

3. Environment

• Lower (warm) water consumption

• Less detergent • Lower energy consumption (energy consumed only during milking)

4. Technology

• Milk/air separator

• Milk pump

• Milk measurement • Take-off

• Vacuum generator (electronically regulated ejectors)

• Buffer

• PLC, display and communication

• Viewable milking process • Quality control and calibrating ex works

• Appropriate in AMS (automatic milking system) and traditional system

• Plug-and-play milking device

5. What is NO LONGER absolutely necessary:

• Vacuum pump • Central vacuum system

• Separate cylinder purchase

• Low-lying milk pump • Central milk/air separator

• Central milk pump

• Milk meter in the milk hose

It will be clear that the foregoing description is intended to illustrate the functioning of preferred embodiments of the invention, and not to restrict the scope of the invention. Starting from the foregoing discussion, a person skilled in the art will immediately think of a large number of variations which come under the spirit and the scope of the present invention.